IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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1. Power requirements
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1.1 UPAMD power adapter electrical characteristics
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A UPAMD power adapter is designed to provide power to any compliant sink device that is rated at more
than 10W, but less than or equal to 240W. The default negotiated voltage is 20V with a maximum of 1A
of current flow. However, smart sink devices may negotiate voltages in the range of 0V – 60V subject to a
maximum output power of 240W and never more than 8A of current.
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1.1.1 Input power
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1.1.1.1 Voltage
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The power supply shall be capable of supplying full rated output power over the input range of 90 VAC
RMS to 265 VAC RMS. Nominal voltage is 120 VAC. The power supply shall be capable of start-up
(power-on) at 90 VAC and 50 Hz minimum.
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1.1.1.2 Power Factor
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Provisions for adding harmonic reduction per EN 61000-3-2 must be present.
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1.1.1.3 Range Switching
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The power supply shall accept the full input range. No range switching is necessary or possible.
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1.1.1.4 Frequency
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The supply shall operate with an input frequency of 47 – 63 Hz AC.
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1.1.1.5 Current
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Maximum steady state input current shall be less than 2.4 Amperes RMS at 90 VAC and maximum load.
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1.1.1.6 Input Power Rating
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The supply true input power is limited to the maximum power the adapter is capable of handling. Since
UPAMD power adapters may provide multiple outputs, the maximum input power rating is dependent upon
the design of the adapter.
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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1.1.1.7 Inrush Current
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Maximum inrush current, from power-on (with power on at any point on the AC sine wave) and including,
but not limited to, three line cycles, shall be (*** Cannot locate an IEC requirement we can reference.
Too be completed by Power Subgroup***)
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http://www.top40-charts.info/?title=Inrush_current
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1.1.1.8 Input Protection
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a)
Under Voltage: The power supply shall not be damaged by applying an input voltage below the
minimum specified in Section 1.1.1.1.
b)
Line Transient: The power supply shall operate within Specifications under the following
conditions: Transients as defined in IEC 801-4.
c)
Catastrophic Failure Protection: When any single component fails, the power supply will not
exhibit any of the following effects:
d)
i)
Startling noise
ii)
Flame
iii)
Excessive smoke
iv)
Charred PCB
v)
Fused PCB conductor
vi)
Dielectric breakdown
AC Leakage Current: Class I Equipment (Grounded Equipment)
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(***We want to reference a standard. Is it enough to put criteria as we have done for the low-energy
requirements, on the output? Must we also specify input leakage current limits?***)
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Do we need requirements for isolation? – Standards apply mostly to medical, direct attachment to
patient treatment equipment. IEC 61000-1-3. Limits to 27A.
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1.1.2 Output power
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Output power requirements for the UPAMD power adapter are discussed in the remaining sections.
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1.1.2.1 Output Protection
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(***We want to reference a standard. What standards exist for over-current, over-voltage and overtemperature limits? Are there any standards for maximum moisture, temperature, dust or vibration
requirements we need to include?***)
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1.1.3 Non-ignition source and low, stored energy
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UPAMD power adapters shall have a low energy level at any time a charged connector is exposed. Stored
capacitive energy of the source and cable would be limited to 8.0uJ. Stored inductive energy of the source
output, cable and device input shall be limited to 4.7uJ. These maximum capacitive and inductive energy
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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levels fall within the maximum limits defined in IEC 60950-1 for the range of voltages and currents
UPAMD supports during any time when the connectors are not mated, exposing the pins.
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UPAMD power adapters shall meet the Human Body Model and Machine Body Model ESD requirements
as specified in IEC 61000-4-2, IEC 61204-3 (EN 61204-3 in EU) Low voltage power supplies with DC
output – Part 3: Electromagnetic Compatability (EMC).
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1.2 UPAMD connector pin definitions
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UPAMD has defined a 6-pin connector that consists of:
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
VPlus Positive Power Connection: provides voltage and current to a sink to power its power
communications circuit or the entire sink device. There are two VPlus power terminals, for
redundancy.
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
CANH Connection: serves a dual purpose. This pin is used to determine device connect or
disconnect status as well as to provide data communication between UPAMD power adapter and
sink device.
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
CANL Connection: part of a differential pair.
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
VNeg Negative Power Connection: provides the electrical ground. There are two VNeg power
pins, for redundancy.
NOTE—If CAN-bus is not chosen for the communications layer, the communication connection pins
will be renamed. This document will be revised to use whatever definition the Communications and
Connector subgroups define. These pin definitions are here to facilitate understanding of the
sections that follow.
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1.3 UPAMD power states
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A UPAMD power adapter has five unique connection-related states:
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
No sink device connected
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
Sink device is connected without digital power communication capability (dumb sink)
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
Sink device is connected with digital power communication capability (smart sink)
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
A Source/Sink device with digital power communication capability is connected (device is capable
of being either a source or sink of power and reversing its role through negotiation)
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
Error condition (improper signal on Comm1.)
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1.3.1 Input power applied to UPAMD power adapter
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A UPAMD power adapter shall prior to setting any output power check to determine if it is connected to
another UPAMD power source instead of a sink. This is done by checking for voltage above 3V on the
Power pin that might be set by another UPAMD power source with which it might happen to be connected.
If the adapter is connected to another power source, it shall execute the source negotiation protocol that will
enable it to either:
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a.
Choose to reverse its role and become a sink, or
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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b.
Request the connected source reverse its role to become a sink, or
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c.
Operate in an idle state, neither accepting nor supplying power.
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If the adapter is not connected to another power source as determined by a voltage measurement of < 3V on
the Power pin, then the adapter enters the device connect detection procedure described in the next
sections.
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When two sources are connected together, the source with the highest priority gets to choose its role as part
of the power negotiation protocol.
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1.3.2 Sink device disconnected
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When input power is applied to a UPAMD power adapter, the output connector shall have the following
voltages on the UPAMD connector pins.
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a.
VPlus / VNeg: unpowered. VPlus / VNeg may have a very small residual voltage due to
capacitance from connection and disconnect with other devices, but never more than the low
stored energy requirements specified in section 1.1.3, above.
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b.
CANH: Signal Voltage @ __mA (What is the tolerance - +/- xx%?) To be defined.
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c.
CANL: second half of differential pair.
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No device connected is indicated by measuring current across two sides of a 1-10 ohm resistor. If no
device is connected, no current will flow.
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1.3.3 Sink device connected
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A sink is determined to be connected to a UPAMD power adapter when current flows across two ends of a
1 – 10 ohms resistor on CANH. CANH and CANL voltages were set during the initialization procedure to
a differential of 3V. As long as no sink is connected, the circuit remains open and no current flows,
indicating no device is connected.
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A dumb sink shall terminate CANH to ground through an xxxx ohm resistor, causing current to flow,
indicating a device is now connected to the power adapter. A smart sink shall terminate CANH to ground
through a 120 ohm resistor, causing current to flow, indicating a device is now connected.
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Current flow greater than __mA is an error condition. The UPAMD power adapter shall limit power on
CANH to a maximum of __mW.
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The UPAMD power adapter shall continuously monitor the current flow on CANH and must, within
1.87ms, determine when the CANH or CANL pins in the connector have separated and discharge the
power in VPlus and VNeg to unpowered. Unpowered is an open circuit that shall have no more than 0.1uF
capacitance including cable, connector, and all components in the line. A short circuit at this stage shall
supply no more than 25mA with no more than 15mH inductance. CANH and CANL always disconnect
prior to power pins separating from the mating connector. Maximum supported acceleration of separation
of connectors is 30m/s2. Any higher disconnect speed shall be considered abnormal and outside of the
scope of non-ignition, low stored energy requirements in the UPAMD standard.
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NOTE-- The voltage and current limits on the Power pin were chosen to be under the non-ignition
maximum voltage and power level defined in UL 60601-1. Using 12V provides sufficient power to the
communications circuit in any sink during power negotiation stages, without having to supply more than
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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the non-ignition maximum current flow. Whereas using 5V, could result in a sink needing more current
than is allowable as a non-ignition source.
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1.3.3.1 Connected to a dumb sink
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After determining that the UPAMD power adapter is connected to a dumb sink, it shall set the voltage
differential between VPlus and VNeg to 21V +/- 10% with a maximum allowable current draw of 1A.
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1.3.3.2 Connected to a smart sink
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After determining that the UPAMD power adapter is connected to a smart sink, it shall set the voltage
differential between VPlus and VNeg to 21V +/- 10% with a maximum allowable current draw of 1A. At
this stage, the smart adapter exchanges messages with the sink and may negotiate higher power (see
Available Power and Requested Power message types in section xxxx.)
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The UPAMD then sets the voltage and current limit as specified in the negotiated messages, if different
than the 20V @ 1A default limit.
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1.4 Measuring voltage and current
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UPAMD power adapters may terminate in a female connector at the adapter or they may have a nonremovable cable that terminates in a male cable. In the case of a female connector termination, a UPAMD
power cord that terminates in a male connector on both ends is used to connect the adapter to a sink device.
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In the case of a fixed power cord that terminates in a male connector, measuring compliant voltage and
current shall be done at the male connector VPlus and VNeg power pins. In the case of an EPS that
terminates in a female connector that allows for a UPAMD power cord to be connected, measurements
shall be made using a UPAMD certified power cord that is connected to the adapter. Measuring compliant
voltage and current shall be done at the disconnected end of the attached cable on the male connector VPlus
and VNeg power pins.
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1.5 Maximum voltage drop requirements
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A UPAMD power adapter may contain one or more female connectors that accept UPAMD power cords
for connecting to sink devices. Power cords may be of various lengths and may use wiring of different
gauges. In order to ensure the output voltage received by the sink is compliant with the voltage specified in
sections 1.3.3.1 and 1.3.3.2, cables and connectors, whether fixed or detachable, shall have a maximum
allowable resistance of 100 mohms, regardless of cable length.
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1.6 Grounding
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To be discussed.
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1.7 Unstable input power conditions
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To be discussed.
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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1.8 Efficiency
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To be discussed.
IEEE P<designation>/D<draft_number>, <draft_month> <draft_year>
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Annex A
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(informative)
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Bibliography
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